Chlamydia is known as a ‘silent’ infection because most infected people are asymptomatic and lack abnormal physical examination findings. Estimates of the proportion of chlamydia-infected people who develop symptoms vary by setting and study methodology; two published studies that incorporated modeling techniques to address limitations of point prevalence surveys estimated that only about 10% of men and 5-30% of women with laboratory-confirmed chlamydial infection develop symptoms.The incubation period of chlamydia is poorly defined. However, given the relatively slow replication cycle of the organism, symptoms may not appear until several weeks after exposure in those persons who develop symptoms.
In women, the bacteria initially infect the cervix, where the infection may cause signs and symptoms of cervicitis (e.g., mucopurulent endocervical discharge, easily induced endocervical bleeding), and sometimes the urethra, which may result in signs and symptoms of urethritis (e.g., pyuria, dysuria, urinary frequency). Infection can spread from the cervix to the upper reproductive tract (i.e., uterus, fallopian tubes), causing pelvic inflammatory disease (PID), which may be asymptomatic (“subclinical PID”)or acute, with typical symptoms of abdominal and/or pelvic pain, along with signs of cervical motion tenderness, and uterine or adnexal tenderness on examination.
Men who are symptomatic typically have urethritis, with a mucoid or watery urethral discharge and dysuria. A minority of infected men develop epididymitis (with or without symptomatic urethritis), presenting with unilateral testicular pain, tenderness, and swelling.
Chlamydia can infect the rectum in men and women, either directly (through receptive anal sex), or possibly via spread from the cervix and vagina in a woman with cervical chlamydial infection.While these infections are often asymptomatic, they can cause symptoms of proctitis (e.g., rectal pain, discharge, and/or bleeding).
Sexually acquired chlamydial conjunctivitis can occur in both men and women through contact with infected genital secretions.
While chlamydia can also be found in the throats of women and men having oral sex with an infected partner, it is typically asymptomatic and not thought to be an important cause of pharyngitis.